Installation of the series capacitor compensation (short for: SC) device on an existing circuit can shorten the electrical distance efficiently, while the occupation of the land resources is minimal, it is also the efficient technical means of enhancing the transmission capacity of the transmission line.
Series capacitor compensation device is composed of a series capacitor, a metal oxide voltage limiter MOV, a spark gap and other major equipment. The spark gap is the main protection of the MOV and the backup protection of the series capacitor, therefore it has a great demand on the working reliability, wherein the spark gap divider is a very important ancillary equipment of the spark gap, the working state of the spark gap divider relates directly to whether the spark gap can regular trigger when the line has a failure, which is one of the keys to guarantee the spark gap can work safely and reliably.
When the line installed in the series compensation device or the adjacent line goes wrong, the line current flows cross the series capacitor, resulting in the higher voltage being generated on both ends of the series capacitor. In order to prevent the capacitor being damaged by the high voltage, it needs to trigger the spark gap, quickly bypass series compensation in the series capacitor. Accordingly, the series compensation control protect device will issue the trigger order to the spark gap trigger control circuit, and the spark gap control circuit, after receiving the order of the series compensation control protect system, determines weather the systems has reached the preset threshold voltage. When it reaches the threshold voltage, the spark gap trigger control circuit will generate the ignition pulse. The spark gap control circuit gains the real time voltage form divider return circuit. Once the spark gap divider breaks down, it will cause the spark gap trigger control device not be able to get the accurate voltage value, which causes malfunction.